This invention relates generally to an apparatus for treating metal and more particularly concerns an apparatus for accurately and reliably controlling a wash system that cleans and pretreats metal prior to painting.
Many manufacturers who use metal in their products require the metal to be treated prior to its use. This treatment may comprise pressing the metal, forming the metal, cleaning the metal, painting the metal, etc., or could comprise a combination of such treatments. Regardless of the required treatment, the end product must meet the specifications set forth by the manufacturer so that it can be used by the manufacturer to produce the manufacturer""s products. Any delay in the treatment of the metal will likely delay the manufacturer""s ability to produce its products, and will likely result in increased costs and/or loss of profits due to inefficiency. As such, it is essential that the metal treatment process operate smoothly, efficiently, and on time.
This task can often be more difficult than it sounds. For example, many manufacturers require that the metal used in their products be washed prior to its use. Typically this type of treatment requires the metal workpiece to be attached to a transportation system of some type (e.g., a conveyor or indexing system) and run through a multi-staged wash process. The wash process could include one or more soaking stages, cleaning stages, additional rinsing stages, and drying stages. If the workpiece is not monitored, and the treatment process not controlled, the metal product exiting the washing treatment process may not be cleaned to the specifications set forth by the manufacturer and may require additional washing of the metal workpiece before it can be used. Such delays cost money and loss of profits as discussed above. In addition, the metal workpiece may require further treatment once it is removed from the washing process. For example, the workpiece may also need to be painted prior to the manufacturer using it. Such additional treatment may create further demands that the washing treatment process be done correctly and efficiently.
As a solution to these problems, prior attempts have been made to monitor and control the treatment processes of metal. For example, U.S. Pat. No. 5,831,855, issued Nov. 3, 1998, to Kinsman, discloses a monitoring system for the electrostatic powder painting industry. This monitoring system senses the pH of the recycled cleaning-surface activation solution, the temperature of the curing zone, delivery container weight, and line speed. The monitoring system disclosed, however, does not monitor some of the essential parameters required in order to provide accurate and reliable control of the metal treatment process. In addition, the disclosed metal treatment control system does not provide for selective monitoring and controlling of the metal treatment process.
Another problem with the metal treatment control systems of today is that they do not provide appropriate alarm and communication systems capable of generating various types of alarms detailing when a problem occurred, in what stage it occurred, etc. Of most concern is that the systems do not provide remote access and monitoring features which allow individuals who are removed from the immediate vicinity of the treatment controlling apparatus to access, monitor, control and/or receive alarm notifications from the control system. For example, current systems for controlling treatment of metal require a plant manager, line supervisor, or line operator to go to the control system, determine what triggered the alarm, and take some corrective action to fix the situation. Typically the line operator will attempt to solve the problem. If the line operator cannot figure out a solution, the line supervisor will be called upon to try and answer the problem. If the line supervisor also cannot figure out a solution, the plant manager (or next person in the chain of command) will be called upon to correct the problem. Depending on the number of people in the chain of command this may repeat several times. This system of operation works well if the people needed to answer the problems are on-site or immediately available, however, sometimes the persons called upon to answer the problems are not in the office, (e.g., the person is on a business trip, at home, on vacation). Often this person is still called to assist in solving the problem and may be asked to come in and fix the problem if his or her assistance over the phone is not sufficient. This is not only inconvenient to the employee, but is inefficient as well.
Another problem prevalent in the metal treatment control systems of today is that the systems are subject to intentional and/or accidental tampering due to uncontrolled access to the control system. Since different people may need to have access to the control system, as discussed in the example above, modem systems do not require password protection and/or authorization codes prior to allowing persons to alter the exemplary or desired ranges/parameters set in the control system, nor do they make such systems feasible (e.g., many people have to have access in case the people in charge are out). If any of the programed values (or desired parameters) get changed, the control system may allow the treatment process to continue despite the fact that it is operating out of the required specification, (e.g., it thinks its operating within specification because the value it is using to compare the parameters to is incorrect).
Thus it is apparent that needs exist for an apparatus for controlling treatment of metal which allows for: more accurate system monitoring; selective operation; monitoring and controlling additional essential parameters of the treatment process; and remote access, monitoring and control.
An apparatus for treating metal that is capable of selectively monitoring and controlling various aspects of a multi-staged metal treatment process to more accurately and reliably administer treatment is described herein. The treatment process employs an aqueous-based system monitored and controlled by a controller that detects when various portions of the process have departed from, or are operating outside of, specified parameters and takes preventative, or corrective, action to maintain the system within the specified parameters.
In a first and second stage of the treatment process, a metal workpiece is washed by an alkaline cleanser which is monitored by the controller for temperature and solution conductivity. The controller operates output actuators, such as a chemical feed pump, to ensure that these stages are performed within the specified parameters. As the controller detects that a monitored condition is departing from, or is operating outside of, a specified parameter, the controller directs an output actuator to perform a specified function, (e.g., adding a particular chemical) so that the monitored condition returns to the desired parameter. In a third and fourth stage, the workpiece is rinsed by an aqueous solution to remove the cleanser and monitored by the controller for temperature and solution conductivity. The workpiece is then subjected to a conditioning stage whereby a water soluble ionic solution (or activator) is applied as an aqueous media and the controller monitors the conductivity and pH of the activator to ensure that the desired parameters for the treatment process are met. In a sixth stage, an iron phosphate is applied to the workpiece and the solution temperature, conductivity and pH are monitored by the controller to ensure that the proper concentration of chemicals exists so that the metal will be coated according to the desired parameters. The controller may activate output actuators to assist it in maintaining the parameters. The workpiece is then subjected to seventh and eighth rinse stages where the controller monitors the conductivity of the rinsing solution. In a ninth stage of the treatment process, a finishing overcoat is applied as an ionic aqueous sealing agent over the phosphate layered workpiece and the controller monitors the conductivity and pH values of the agent to maintain proper concentration of chemicals and conform with the specified parameters of the treatment system. Lastly, the workpiece is rinsed with de-ionized water while the controller monitors the rinse solution""s conductivity.
More particularly, the metal treatment controlling apparatus comprises sensors for monitoring parameters of the multi-staged process at various stages throughout the process. In keeping with the invention, the sensors may comprise pH sensors, conductivity sensors, temperature sensors, pump sensors, etc. Such sensors provide valuable feedback from various stages of the metal treatment process and allow the stages, as well as the system as a whole, to be monitored and run more efficiently. In particular, a conductivity sensor can be used throughout all stages of the treatment process to ensure that the process is conforming to the desired parameters, (e.g., monitoring conductivity to determine solution concentration and/or contamination).
The apparatus further comprises a controller for selectively monitoring the sensors and controlling the metal treatment process to ensure that the treatment is applied according to desired standards throughout. The controller provides at least a first mode and a second mode of controlling the metal treatment process. In the first mode, the controller offers automatic control of the metal treatment process, thereby allowing the system to monitor the process automatically and/or react automatically to the data received from the sensors. In the second mode, the controller offers timed control of the metal treatment process, which results in specified tasks being performed at predetermined time intervals. A combination of automatic and timed controlling can also be achieved so that different stages of the metal treatment process can be set up to run differently, (e.g., one stage can be set for automatic, while another can be set for timed).
The metal treatment control apparatus also comprises output actuators which perform tasks specified by the controller to ensure that the treatment process continues to run within the desired parameters. In keeping with the invention, the output actuators may comprise feed pumps, alarms, conveyor motors, sprayers, ovens, etc. Such output actuators provide the controller with valuable tools to take action to keep the system operating within the desired parameters. For example, if the controller receives input from the sensors indicating that a particular parameter is straying from its desired value, (e.g., pH is straying from the desired pH range), then the controller, via the output actuators, can take corrective or preventive action to keep the particular parameter within its desired value, (e.g., add pH-adjusting chemical to get pH parameter to desired range/value).
The apparatus for controlling treatment of metal may also comprise a communication device capable of generating various types of alarms, (e.g., pH value has strayed from the desired range/value), and further capable of providing remote access to the control apparatus so that individuals who are removed from the immediate vicinity of the treatment controlling apparatus can access, monitoring and/or control system from wherever they are. In addition to notifying the individuals working on or near the treatment controlling apparatus to see and/or hear an alarm, the communication device also can be set up to notify someone off site or away from the apparatus. Additional parties, such as the apparatus manufacturer, may be notified of the alarm and/or allowed to access the apparatus so that they might provide better customer service or assistance.
The apparatus for controlling treatment of metal may also comprise a security component which requires entry of a password or authorized code in order to gain access to the apparatus and/or alter the desired values or parameters. Such a feature serves to minimize the risk of accidental or intentional tampering with the specification settings (or desired parameters) and assist the apparatus in providing accurate and reliable monitoring and/or control of the treatment process.